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"This
material was prepared by resident physicians in partial fulfillment of
educational requirements established for the Postgraduate Training Program =
of
the UTMB Department of Otolaryngology/Head and Neck Surgery and was not
intended for clinical use in its present form. It was prepared for the purp=
ose
of stimulating group discussion in a conference setting. No warranties, eit=
her
express or implied, are made with respect to its accuracy, completeness, or=
timeliness.
The material does not necessarily reflect the current or past opinions of
members of the UTMB faculty and should not be used for purposes of diagnosi=
s or
treatment without consulting appropriate literature sources and informed
professional opinion."

Introd=
uction

Laryngomalacia is the leading cause of stridor in
infancy. It is the most common laryngeal anomaly of the newborn followed by
subglottic stenosis and bilateral vocal fold paralysis. It is characterized=
by
flaccidity of the supraglottic structures, which prolapse inward during
inspiration leading to upper airway obstruction.

Etiology

Review of literature suggests that there are thr=
ee
basic theories that attempt to explain the development of laryngomalacia. T=
hese
are

1)&n=
bsp;
Cartilage Immaturity Theory

2)&n=
bsp;
Theory of Anatomic Abnormality and

3)&n=
bsp;
Neuromuscular Immaturity Theory.

Cartilage Immaturity Theory

Cartilage Immaturity Theory was first proposed by
Sutherland and Lack in the late 19th century. According to this
theory laryngeal flaccidity develops due to delayed maturation of the
cartilageneous support of the larynx. This theory has since been disproved
because there is no evidence of chondropathy in these patients. According to
the Theory of Anatomic Abnormality, laryngomalacia is an exaggeration of the
normal anatomic features of an infant larynx. The infant larynx is softer, =
more
pliable, and easily prone to mucosal edema. There can often be an omega- sh=
aped
epiglottis. Exaggeration in o=
ne or
more of these anatomic features may lead to laryngomalacia. The most accept=
ed
theory is that of neuromuscular immaturity which suggests that laryngeal
hypotonia occurs due to delayed neuromuscular control of the larynx. The
prevlance of other neurological disorders in infants with laryngomalacia
supports this hypothesis.

Association with Reflux

It has been found that there is a strong associa=
tion
of GERD with laryngomalacia and studies have found that 80-100% of infants =
with
laryngomalacia will also have reflux. It is unclear however, whether GERD i=
s a
cause or an effect of the respiratory obstruction. It has been proposed that
the fixed respiratory obstruction in laryngomalacia leads to a large negati=
ve
intrathoracic pressure, which in turn leads to reflux and worsening larynge=
al
edema and obstruction. In addition, the vagal tone to the lower esophageal
sphincter may be reduced contributing to the reflux. These observations
underscore the importance of empiric reflux therapy in patients with
laryngomalacia.

Risk Factors

Risk factors for severe laryngomalacia include: =

1)&n=
bsp;
Prematurity- Although premature infants do not
necessarily have a higher incidence of laryngomalacia, they tend to develop=
the
more severe form of this condition.

2)&n=
bsp;
Neuromuscular disorders- As mentioned earlier, ther=
e is
a higher incidence of neuromuscular disorders in patients with laryngomalac=
ia
and the condition tends to be severe in such patients.

3)&n=
bsp;
Synchronous airway lesions- These can be seen in 10=
-20%
of patients with laryngomalacia. Tracheomalacia and subglottic stenosis have
been reported to be the commonest lesions, though bronchomalacia,
pharyngomalacia and an associated vallecular cyst may also occur. The prese=
nce
of synchronous airway lesions potentiates GERD and also increases the risk =
of
surgical failure.

Classification of Laryngomalacia

There are various types of laryngomalacia and va=
rious
classification schemes have been attempted to correlate type with severity =
and
treatment. For the sake of our presentation, we have classified laryngomala=
cia
into mild, moderate or severe depending upon history, physical exam and
flexible laryngoscopy findings. One can describe the location of the
laryngomalacia as anterior (the epiglottis prolapses posteriorly into
the airway), lateral (AE folds and the cuneiform or corniculate
cartilages prolapse medially into the airway) and posterior (the
redundant mucosa over the arytenoids prolapses anteriorly into the airway).
Laryngomalacia may present as a combination of these subtypes.

Making the Diagnosis

The majority of the infants are diagnosed in the=
first
few weeks of life. High pitched inspiratory stridor is the hallmark of this
condition and the stridor is worsened with activities such as crying, feedi=
ng
or being placed in the supine position. Reflux and feeding symptoms such as
choking, recurrent emesis, prolonged feeding time, cough and weight loss may
also be seen. 10-20% of patients with laryngomalacia may present with
complications such as life threatening airway obstruction, severe weight lo=
ss,
failure to thrive, severe apnea, cyanosis, pulmonary hypertension,
developmental delay and cardiac failure.

Diagnosis of this condition is primarily clinica=
l. A
combination of history, physical examination and flexible laryngoscopy is
sufficient to make a diagnosis in the majority of cases. Flexible laryngosc=
opy
should be carried out in an awake child to assess the type and severity of
laryngomalacia, look for synchronous airway lesions, hunt for signs consist=
ent
with GERD, and also to assess=
vocal
fold mobility. It is important to realize that flexible laryngoscopy does n=
ot
allow adequate visualization of the subglottis or trachea. Complementary
studies may be done in some cases. Chest radiographs can aid in evaluation =
of
potential lower respiratory anomalies such as tracheomalacia, innominate ar=
tery
compression, vascular rings, and signs of aspiration. An esophagram may be =
done
to document the extent and degree of reflux but can also help rule out a
concomitant motility disorder or extrinsic compression from vascular
structures. Sleep studies sho=
uld be
done if the presenting symptoms are sleep apnea or if symptoms fail to impr=
ove
after surgery. A pH probe study should be done prior to consideration of a =
Nissen’s
fundoplication for reflux.

Management Strategies

For the sake of this presentation, management of=
a
child with laryngomalacia is divided into medical and surgical treatment.
Medical management includes empiric reflux therapy, feeding modifications a=
nd
posture repositioning. Empiric reflux therapy may be started with H2 recept=
or
antagonists (ranitidine 3mg/kg three times daily) or proton pump inhibitors
(1mg/kg daily). In more severe cases, 6mg/kg of ranitidine at night along w=
ith
1mg/kg of a PPI daily may be required. Feeding modifications include pacing,
thickening formula feeds, upright feeding position, and giving the infant
small, frequent meals. All parents are instructed on following reflux
precautions. These help the baby feed adequately and maintain weight.

Laryngomalacia is a self limiting condition in 8=
5-90%
of patients. Absolute indications for surgery include cor pulmonale, pulmon=
ary
hypertension, hypoxia, life threatening airway obstruction, apnea, recurrent
cyanosis, failure to thrive, pectus excavatum, and stridor with significant
retractions. Relative indications include aspiration, difficulty feeding a
child who has failed medical intervention and weight loss with feeding
difficulty. One simple measure is to routinely plot these children on the
growth curve to ensure they are gaining weight appropriately. There are no
absolute contraindications for surgery. Weight and age are not
contraindications for surgery. The surgeon should proceed with caution in
patients with laryngomalacia and other neurological disorders or patients w=
ho
have multiple levels of obstruction because these conditions are associated
with a higher failure rate. Preoperative counseling is a must and the paren=
ts
should be advised regarding improvement in feeding and stridor. Though the
feeding improvement is early and often dramatic, the stridor may take a lon=
ger
time to resolve. Parents are also advised about the risks and benefits of
surgery, including the possibility of postoperative intubation, overnight I=
CU
stay, abnormal scarring and the risk of revision surgery. Parents and prima=
ry
care physicians must be reminded about the importance of continuing reflux
precautions and reflux medications post-operatively.

Supraglottoplasty is the most common procedure f=
or
laryngomalacia practiced today. This surgery is designed to trim the AE fol=
ds
and remove the excess mucosa over the arytenoids. The procedure is carried =
out
under general anesthesia with the child breathing spontaneously. The surgic=
al
set up is the same as that for suspension microlaryngoscopy. It is importan=
t to
assess the tracheobronchial tree and vocal fold mobility prior to the
procedure. The surgery may be performed with cold instruments, CO2 laser,
micordebrider or a combination of these. While incising the AE folds, it is
important not to extend the incision beyond the anterior edge of the aryten=
oids
and the incision should not involve the pharyngoepiglottic fold. While remo=
ving
the mucosa over the arytenoid cartilages, one should be gentle and diligent=
to
preserve the interarytenoid mucosa to prevent supraglottic stenosis. Any
bleeding during the procedure is easily controlled with afrin pledgets.

Epiglottopexy is a relatively new procedure indi=
cated
if the level of obstruction is at the level of the epiglottis. Some authors
have presented this as the treatment for any patient with laryngomalacia wi=
th
good surgical outcomes. In this procedure, the mucosa over the lingual surf=
ace
of the epiglottis is denuded either with cold instruments or more recently =
with
CO2 laser in a linear fashion. Important complications associated with this
surgery include aspiration and supraglottic stenosis.

Tracheostomy is rarely performed today for
laryngomalacia alone. Specific indications for tracheostomy include presenc=
e of
> 3 comorbidities, severe sleep apnea documented on a sleep study and
persistence of symptoms after revision supraglottoplasty.

Post-operative care includes overnight stay in t=
he
hospital, monitoring of airway symptoms and feeding improvement. The child =
may
feed as soon as he is awake. Postoperative steroids may be given and reflux
therapy is continued. The parents are asked to follow up in 2-4 weeks time =
and
monitor the child for any worsening symptoms.

The most feared complication is supraglottic ste=
nosis which
is difficult to treat.This c=
an be
avoided by meticulous and very conservative surgery.In some cases, it may prove useful=
to
operate on only one side at a time.

Summary

Laryngomalacia is the commonest cause of
“stridor” in the newborn. It is a self-limiting condition in the
vast majority of cases, and patients with this condition expect symptom
improvement and resolution of stridor by 2 years of age. It is vital for
parents to know that the condition may worsen around 4-6 months of age befo=
re
it gets better. High pitched inspiratory stridor is the hallmark clinical
presentation. Feeding difficulties and GERD are seen in 80-100% of patients
with laryngomalacia. Diagnosis is usually established by history, physical
examination and flexible laryngoscopy findings. Empiric reflux therapy is
indicated for many patients and the more severe cases may benefit from a
combination of medical treatment and surgery. Surgical success in selected
patients with severe laryngomalacia is >90% in several studies.In unusual or worsening cases of
“laryngomalacia”, the otolaryngologist should have a low thresh=
old
for recommending a formal airway evaluation in the operating room.